阅读说明：本技术 带短路保护的低功耗电源管理电路 (Low-power-consumption power management circuit with short-circuit protection ) 是由 曾国兴 孙晓安 黄穗 李楚 于 2021-07-07 设计创作，主要内容包括：本发明公开了一种带短路保护的低功耗电源管理电路,包括控制芯片、负载开关、负载分压电路、使能按键和供电部,其中,所述控制芯片的使能脚连接负载开关,控制负载开关的打开和关闭；负载分压电路对负载开关输出的电压进行分压后输入控制芯片的关断脚,在输入关断脚的电压低于预设值时,控制芯片的使能脚输出低电平,关闭负载开关；所述负载开关向后级电路输出供电。本发明实现了电池和后级电路的隔离,当后级电路发生短路时,能够自动及时的将电池和电路之间断开。避免电池在短路情况下发热,自燃等危险。在工作时,当电池电压下降到一定值时,自动将电池和后级电路断开,避免由于过度放电损坏电池。(The invention discloses a low-power-consumption power management circuit with short-circuit protection, which comprises a control chip, a load switch, a load voltage division circuit, an enabling button and a power supply part, wherein an enabling pin of the control chip is connected with the load switch to control the on and off of the load switch; the load voltage dividing circuit divides the voltage output by the load switch and then inputs the voltage into a turn-off pin of the control chip, and when the voltage input into the turn-off pin is lower than a preset value, an enable pin of the control chip outputs a low level and turns off the load switch; the load switch supplies power to the output of the post-stage circuit. The invention realizes the isolation between the battery and the rear-stage circuit, and can automatically and timely disconnect the battery and the circuit when the rear-stage circuit is short-circuited. The dangers of heating, spontaneous combustion and the like of the battery under the condition of short circuit are avoided. When the battery voltage drops to a certain value during working, the battery is automatically disconnected from a post-stage circuit, so that the damage to the battery due to over-discharge is avoided.)

1. A low-power consumption power management circuit with short-circuit protection is characterized by comprising a control chip, a load switch, a load voltage division circuit, an enable key and a power supply part, wherein,

the enabling pin of the control chip is connected with the load switch to control the on and off of the load switch; the load voltage dividing circuit divides the voltage output by the load switch and then inputs the voltage into a turn-off pin of the control chip, and when the voltage input into the turn-off pin is lower than a preset value, an enable pin of the control chip outputs a low level and turns off the load switch; the load switch outputs power supply to the rear-stage circuit;

the enabling key is in a disconnection state by default, and when the enabling key is pressed for no more than 1s, the enabling pin of the control chip outputs a high level and turns on the load switch; when the enable pin of the control chip outputs high level and the enable key is pressed for more than 2s, the enable pin of the control chip outputs low level and the load switch is closed;

the power supply part supplies power to the control chip and the load switch.

2. The low power consumption power management circuit with short circuit protection as claimed in claim 1, wherein the power supply portion comprises a battery power supply circuit, an external power supply circuit and an external voltage-dividing circuit, wherein the battery power supply circuit respectively supplies power to the control chip and the load switch, and the battery power supply circuit comprises a battery; the external power supply circuit outputs electric energy to the control chip, meanwhile, the external power supply circuit is connected with a voltage detection pin of the control chip through the external voltage circuit, and when the voltage transmitted by the external power supply circuit is smaller than a threshold value, an enabling pin of the control chip is pulled down, namely, the load switch is closed.

3. The low power consumption power management circuit with short circuit protection as claimed in claim 2, wherein the battery power supply circuit further comprises a diode connected in series between the battery and the control chip, the diode having a positive electrode connected to the battery and a negative electrode connected to the control chip.

4. The power management circuit with short-circuit protection and low power consumption of claim 2, wherein the external power supply circuit comprises a USB socket and a diode, the diode is connected in series between the USB socket and the control chip, the anode of the diode is connected to the USB socket, and the cathode of the diode is connected to the control chip.

5. The low power consumption power management circuit with short circuit protection as claimed in claim 2, wherein the external voltage circuit comprises two resistors connected in series, and the connection between the two resistors is connected to the voltage detection pin of the control chip.

6. The low power consumption power management circuit with short circuit protection as claimed in claim 2, further comprising a charging circuit to charge the battery.

7. The low power consumption power management circuit with short circuit protection as claimed in claim 1, wherein the control chip model is LTC 2955.

8. The low power consumption power management circuit with short circuit protection as claimed in claim 1, wherein the load switch comprises a TPS22929D chip or a TPS22916C chip.

9. The low power consumption power management circuit with short circuit protection of claim 6, wherein said charging circuit comprises an LTC4069 chip.

Technical Field

The invention belongs to the field of medical instruments, and particularly relates to a low-power-consumption power management circuit with short-circuit protection.

Background

Batteries are required to be assembled in the cochlear implant external unit, and the size of the conventional battery power supply equipment (namely the cochlear implant external unit in the field of cochlear implants) is smaller and smaller, so that the size of the internal battery is smaller and smaller. For equipment with batteries, it is a challenge to reduce the consumption of batteries by its own circuit as much as possible before the equipment is used by customers after the equipment manufacturer finishes production and stores in a warehouse. In addition, when accidents such as short circuit occur in the rear-stage circuit of the power supply equipment, how to protect the battery from being damaged also has a challenge.

Disclosure of Invention

In view of this, the present invention employs a load switch and two voltage dividing resistor circuits to monitor the output voltage. When the voltage after the load switch is abnormal. The two voltage-dividing resistors directly pull down the enabling pin of the load switch through the power supply chip. At which time the load switch has no output. The short circuit of the circuit after the load switch has no influence on the battery.

In order to achieve the above object, the present invention provides a low power consumption power management circuit with short circuit protection, which comprises a control chip, a load switch, a load voltage dividing circuit, an enable button and a power supply part, wherein,

the enabling pin of the control chip is connected with the load switch to control the on and off of the load switch; the load voltage dividing circuit divides the voltage output by the load switch and then inputs the voltage into a turn-off pin of the control chip, and when the voltage input into the turn-off pin is lower than a preset value, an enable pin of the control chip outputs a low level and turns off the load switch; the load switch outputs power supply to the rear-stage circuit;

the enabling key is in a disconnection state by default, and when the enabling key is pressed for no more than 1s, the enabling pin of the control chip outputs a high level and turns on the load switch; when the enable pin of the control chip outputs high level and the enable key is pressed for more than 2s, the enable pin of the control chip outputs low level and the load switch is closed;

the power supply part supplies power to the control chip and the load switch.

Preferably, the power supply part comprises a battery power supply circuit, an external power supply circuit and an external voltage-dividing circuit, wherein the battery power supply circuit respectively supplies power to the control chip and the load switch, and the battery power supply circuit comprises a battery; the external power supply circuit outputs electric energy to the control chip, meanwhile, the external power supply circuit is connected with a voltage detection pin of the control chip through the external voltage circuit, and when the voltage transmitted by the external power supply circuit is smaller than a threshold value, an enabling pin of the control chip is pulled down, namely, the load switch is closed.

Preferably, the battery power supply circuit further comprises a diode connected in series between the battery and the control chip, wherein the anode of the diode is connected with the battery, and the cathode of the diode is connected with the control chip.

Preferably, the external power supply circuit comprises a USB socket and a diode, the diode is connected in series between the USB socket and the control chip, the anode of the diode is connected to the USB socket, and the cathode of the diode is connected to the control chip.

Preferably, the external voltage-dividing circuit comprises two resistors connected in series, and the connection position between the two resistors is connected with the voltage detection pin of the control chip.

Preferably, the charging circuit is further included to charge the battery.

Preferably, the model of the control chip is LTC 2955.

Preferably, the load switch comprises a TPS22929D chip or a TPS22916C chip.

Preferably, the charging circuit comprises an LTC4069 chip.

The beneficial effects of the invention at least comprise:

1. the management of the power supply by one key is realized, namely, the normal power supply and low power consumption switching of the power supply are realized by the enabling key, the service life of the battery can be remarkably prolonged by the low power consumption, and under the low power consumption, the electric quantity of the battery is still sufficient after the product is stored for a long time or transported for a long distance;

2. the isolation between the battery and the rear-stage circuit is realized, when the rear-stage circuit is short-circuited, the battery and the circuit can be automatically and timely disconnected, and the dangers of heating, spontaneous combustion and the like of the battery under the condition of short circuit are avoided;

3. when the battery voltage drops to a certain value during working, the battery is automatically disconnected from a post-stage circuit, so that the battery is prevented from being damaged due to over-discharge;

4. the automatic identification of charging is realized, and the circuit can be set to be automatically turned on to supply power to a post-stage circuit during charging;

5. the external voltage circuit detects the voltage accessed by the USB, and when the voltage is lower than a certain value, the control chip outputs the enabling pin of the load switch to disconnect the power supply of the rear-stage circuit and the battery;

6. the diode is used for isolating external power supply and internal battery power supply, so that the external power supply or the internal power supply can independently supply power to the circuit, or the external power supply and the internal power supply can simultaneously supply power to the circuit without interference, and the diode prevents the power supply from being reversely connected to damage a rear-stage circuit.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a block diagram of a low power consumption power management circuit with short circuit protection according to an embodiment of the present invention;

FIG. 2 is a schematic circuit diagram of a low power management circuit with short circuit protection according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a charging circuit of a low power consumption power management circuit with short-circuit protection according to an embodiment of the present invention.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to fig. 1 and 2, a block diagram and a schematic circuit diagram of a low power consumption power management circuit with short circuit protection according to an embodiment of the present invention are shown, including a control chip 10, a load switch 20, a load voltage dividing circuit 21, an enable button 11 and a power supply portion, wherein,

the enabling pin of the control chip 10 is connected with the load switch 20 to control the on and off of the load switch 20; the load voltage dividing circuit 21 divides the voltage output by the load switch 20 and then inputs the voltage into the off pin of the control chip 10, and when the voltage input into the off pin is lower than a preset value, the enable pin of the control chip 10 outputs a low level and turns off the load switch 20; the load switch 20 outputs power supply to a rear-stage circuit;

the enable key 11 is in a default off state, and when the enable key 11 is pressed for no more than 1s, the enable pin of the control chip 10 outputs a high level to turn on the load switch 20; when the enable pin of the control chip 10 outputs a high level and the enable key 11 is pressed for more than 2s, the enable pin of the control chip 10 outputs a low level and turns off the load switch 20;

the power supply unit supplies power to the control chip 10 and the load switch 20.

The power supply part comprises a battery power supply circuit 31, an external power supply circuit 32 and an external voltage-dividing circuit 33, wherein the battery power supply circuit 31 respectively supplies power to the control chip 10 and the load switch 20, and the battery power supply circuit 31 comprises a battery; the external power supply circuit 32 outputs power to the control chip 10, and the external power supply circuit 32 is also connected to the voltage detection pin of the control chip 10 through the external voltage circuit 33, so that the enable pin of the control chip 10 is pulled down, i.e. the load switch 20 is turned off, when the voltage transmitted from the external power supply circuit 32 is smaller than the threshold value. The battery power supply circuit 31 further includes a diode connected in series between the battery and the control chip 10, wherein the anode of the diode is connected to the battery, and the cathode of the diode is connected to the control chip 10. The external power supply circuit 32 includes a USB socket and a diode, the diode is connected in series between the USB socket and the control chip 10, the anode of the diode is connected to the USB socket, and the cathode of the diode is connected to the control chip 10. The external voltage-dividing circuit 33 includes two resistors connected in series, and a connection point between the two resistors is connected to a voltage detection pin for controlling the voltage of the new resistor.

The battery (the battery can be a general disposable battery or a rechargeable battery) and the system circuit are separated by using the load switch 20, and the power management of the system is realized by combining the load voltage division circuit 21 and the control chip 10.

When the rear-stage circuit of the load switch 20 is short-circuited or the load is too heavy to cause the battery voltage to be reduced, the voltage of the load voltage division circuit 21 is lower than the protection value, and the control chip 10 automatically pulls down the enable pin connected with the load switch 20 after detecting the voltage; the battery and the rear-stage circuit are disconnected, the battery is protected, the problems that the battery generates heat or spontaneously combusts due to short circuit or overlarge circuit and the like are avoided, and the stability of the circuit is enhanced.

When the battery voltage slowly drops to a certain value in normal work, the control chip 10 detects that the voltage is low through the load bleeder circuit 21, pulls down the enabling pin of the load switch 20, and at the moment, the battery and the rear-stage circuit are disconnected, and the whole system circuit enters a low-power-consumption discharge mode, and the experimental test shows that the working current is less than 3uA, so that the over-discharge of the battery can be well protected.

Under normal operating mode, when pressing enable button 11 for a long time and surpassing 2s, load switch 20 disconnection, back level circuit and battery disconnection, the circuit gets into low-power consumption mode, and operating current is less than 3uA, and the static consumption of whole circuit can very big reduction in low-power consumption mode, and the product of electrified battery no matter has been produced storage, or long-distance transport to customer's department, the electric quantity of product can both be kept for a long time.

Because the load voltage dividing circuit 21 is arranged at the rear end of the load switch 20, when the sampling voltage is smaller than the set value, the load switch 20 is closed, and no voltage exists on the load voltage dividing circuit 21 at the moment; meanwhile, because the load voltage division circuit 21 is arranged behind the load switch 20, the static power consumption of the whole circuit after the load switch 20 is turned off can be reduced, and the current consumption of the battery end directly connected with the load voltage division circuit 21 is reduced.

Referring to the circuit schematic of fig. 2, U31 is the load switch 20 and VBAT is the battery voltage. The voltage drop across the load switch 20 is minimal and VBAT2 and VBAT may be considered equal during operation. U31 is the control chip 10 that carries out voltage detection and enable signal, and R116 and R139 constitute load bleeder circuit 21, and R116 and R139 provide voltage for 9 feet (/ KILL) of U35, and 3 feet (EN) of U35 output low level when the partial pressure is less than the setting value, and 3 feet (ON) of U31 load switch 20 is low at this moment, and 1 foot of U31 does not output.

The diodes D18, D19, D20 isolate the VBAT and the USB _ VBUS, the VBAT and the USB _ VBUS can supply power to the U35 independently, or the USB _ VBUS and the VBAT supply power to the U35 simultaneously without interfering with each other, and the diodes D18, D19, D20 can also prevent the power source from being reversely connected to cause the damage of the rear-stage circuit.

The external voltage circuit 33 is divided by the two resistors R120 and R121 to detect the voltage VIN2, the voltage VIN2 is supplied to the USB _ VBUS through the diode D19, the voltage detected by the USB _ VBUS actually detected by the resistors R120 and R121 is provided for the 10 pins (ON) of the U35, when the voltage of the USB _ VBUS is connected, the voltage of the 10 pins (ON) is automatically detected by the U35, and when the voltage is larger than the threshold value of 0.8V, the 3 pins (EN) can be automatically pulled high. The U31 load switch 20 is open to power the subsequent stage.

SW1 is an enable key 11, controls the output state of the 3 pin (EN) of U35, when the EN output is low level, SW1 is pressed for a short time (not more than 1s), the EN pin output is high, and the load switch 20 is opened; when the 3 pin (EN) output is high, SW1 is pressed long (over 2s), the EN pin output goes low and the load switch 20 is closed. SW1 enables switching between a normal operating mode and a low power mode.

The whole circuit has 3 working states: a) normal operation, b) low battery voltage or short circuit of the circuit at the rear stage of the load switch 20, and c) state of charge.

a) When the circuit is in a normal working state. The battery voltage VBAT powers U35 and U31 through diode D20. After the battery is connected to the J5 (battery socket), the 3 pin (EN) of the U35 is set to a low level as a default, the U31 load switch 20 is turned off, the VBAT2 voltage is 0V, and the VBAT2 supplies power to the whole circuit, so that the rear-stage circuit does not work. After SW1 is pressed for a short time, pin 3 (EN) of U35 is pulled high, load switch 20U31 is opened, and then VBAT2 voltage is equal to VBAT, and VBAT2 supplies power to the whole subsequent circuit. When the U31 is in an open state, the SW1 is pressed for a long time (more than 2s), the pin 3 (EN) of the U35 becomes low, the U31 load switch 20 is closed, the battery voltages VBAT and VBAT2 are disconnected, the battery only supplies power to the U35 and the U31, and at the moment, the static working current is less than 3uA, the static working current is extremely low, and the electric quantity of the battery can be kept for a long time.

b) When the battery voltage drops or the circuit is shorted after the load switch 20. The 3 pin of U35 is pulled low and the U31 load switch 20 is closed. The voltage division of two resistors R116 and R139 is monitored by a pin 9 (/ KILL) of U35, when the voltage of the battery is reduced to a set value, namely the voltage of VBAT2 is reduced to the set value, a pin 3 of U35 is pulled low, the load switch 20 of U31 is closed, a rear-stage circuit behind U31 does not work, VBAT only supplies power to U31 and U35, the static working current of the circuit is less than 3uA at the moment, and the battery damage caused by over-discharge of the battery can be avoided. When a rear-stage circuit behind the load switch 20U31 is short-circuited, the voltage of VBAT2 becomes 0V, the divided voltage of R116 and R139 is also 0V and is less than the set 0.8V, at the moment, pin 3 (EN) of U35 is pulled low, the U31 load switch 20 is disconnected, the battery voltage VBAT and the rear-stage circuit VBAT2 are disconnected, the VBAT only supplies power for the U31 and U35 circuits, the circuit enters an extremely low-power-consumption working state, the static working current is less than 3uA, the battery is prevented from entering a short-circuit working state after the load switch 20 is disconnected, the battery is protected, and heating and even burning of the battery due to short circuit are avoided.

c) When the USB socket is powered on, the USB _ VBUS supplies power to the U35 through the D18 and the D19. When pin 3 (EN) of U35 is low, U31 load switch 20 is off and the subsequent circuits are not active. When a USB plug is inserted into the USB socket, the 10-pin (ON) of the U35 detects that the partial voltage of R120 and R121 is greater than the set 0.8V, the 3-pin (EN) is pulled high, and the rear-stage circuit of the U31 load switch 20 is electrified to work; when the voltage detected by pin 10 (ON) of U35 is less than 0.8V, pin 3 (EN) is automatically pulled down, and the subsequent stage circuit of load switch 20U31 is opened.

In a specific embodiment, the model of the control chip can be selected from LTC 2955. The load switch comprises a TPS22929D chip or a TPS22916C chip or a functionally similar chip.

The charging circuit includes an LTC4069 chip or a functionally similar charging chip.

Referring to fig. 3, the embodiment further includes a charging circuit for charging the battery. When the voltage of about 5V is connected to the USB _ VBUS pin, the U36 charging chip charges the battery, the pin 3 of the U36 is connected with the VBAT of the battery, at any time, as long as the voltage of about 5V is connected to the USB _ VBUS pin, the U36 can charge the battery, the pin 2 (CHRG) of the U36 is pulled down during charging, the D4 is lightened to indicate charging, meanwhile, the BAT _ CHARG is at a low level, and a subsequent circuit such as a mcu indicating signal can be given to indicate charging. When the battery is fully charged, pin 2 of U36 (CHRG) goes high, D4 goes off, at which time BAT _ CHARG pin is high, signaling to subsequent circuitry that the battery is fully charged.

When the circuit works normally, the load switch 20 is switched off after the key SW1 is pressed for a long time. At the moment, the rear-stage circuit is disconnected with the VBAT of the battery, the circuit enters low power consumption, and the quiescent current is less than 3 uA. When the machine is in the super power consumption mode, the SW1 is pressed for a short time, the load switch 20 is switched on, the battery VBAT supplies power to the rear-stage circuit, and the circuit enters a normal working state.

The power supply of the circuit is managed through a key, and the switching between the normal operation mode and the ultra-low operating current mode is realized, namely the circuit is controlled to enter low power consumption by the on-off of the load switch 20. The method has low power consumption, can remarkably prolong the retention time of the electric quantity of the battery, and can retain the sufficient electric quantity for a long time no matter the product is stored in a warehouse after being produced or the product is transported for a long distance.

The isolation between the battery and the working circuit is realized, and the connection between the load switch 20 and the battery is automatically disconnected by detecting the voltage change at the load end. When the load switch 20U31 rear end circuit VBAT2 is short-circuited, the divided voltages of R116 and R139 become 0V, and pin 9 (/ KILL) of U35 detects that the voltage is lower than 0.8V, pulling down pin 3 (EN). The U31 load switch 20 disconnects the load from the battery. VBAT supplies power to U31 and U35 only at this time, and the operating current is less than 3 uA. The circuit can be set to have low power consumption by automatically turning off the U31 load switch 20 when VBAT2 is less than a certain value. The calculation formula is as follows: VBAT 2R 116/(R116+ R139) <0.8V automatically turns U31 off, and the resistance of R116 and R139 can be selected according to actual conditions. Meanwhile, the resistors R116 and R139 are placed behind the U31 load switch 20, so that the quiescent operating current of the battery after disconnection can be further reduced, if the resistors R116 and R139 are placed in front of the load switch 20, namely, connected to the VBAT terminal, the resistors R116 and R139 still consume power after the load switch 20 is disconnected, and the resistors R139 and R139 do not consume power after the resistors R31 load switch 20 is placed behind the load switch 20.

The automatic recognition of the access of the external power supply (USB power supply) can be set to automatically turn on the U31 load switch 20 to operate the subsequent circuit when the access of the external power supply circuit 32 is detected. The pin voltage of USB _ VBUS is monitored by the external voltage-dividing circuit 33 composed of R120 and R121 and pin 10 (ON) of U35. When the USB _ VBUS voltage is lower than the set value, the load switch 20 is automatically turned off. The set voltage calculation formula is:

when the voltage is (USB _ VBUS-0.2) × R121/(R120+ R121) <0.8V, the U31 load switch 20 is automatically turned off.

The three diodes D18, D19 and D20 realize the isolation of USB _ VUBS and VBAT, and avoid the mutual interference of the two voltages. The external power supply and the internal power supply can supply power to the circuit independently or simultaneously without influencing each other. Meanwhile, the diode also has the function of preventing the reverse connection of the two power supplies, so that the reverse connection is avoided and the rear-stage circuit is prevented from being damaged.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.